CODEWITHSUNDEEP
data-structureshashmaplanguage-agnostichashtable
user13417435
user13417435

Reputation:

Basic differences between HashTable and HashMap?

I am researching about hash tables and hash maps, everything I have read or watched gives a very vague description of the differences. From messing around on Netbeans with them both, they seem to have the same functions and do the same things, what are the fundamental differences between these two data structures?

Upvotes: 1

Views: 296

Answers (2)

AProgrammer
AProgrammer

Reputation: 52324

HashTable sounds to me like a concrete data structure, although it has numerous variants depending on what happens when a collision occurs, when the table fills up, when it empties.

Map sounds like a abstract data structure, something defined by the available operations (Dictionary would be a potential other name for the same data structure, but I'd not be surprised if some nomenclature defined both with a nuance somewhere).

HashMap sounds like an implementation of the Map abstract data structure using an HashTable concrete data structure.

Again, I'd not be surprised if a language or a library provided both, with a nuance somewhere (HashMap for instance could provide only the operations defined for a Map, but HashTable provides everything which make sense for an HashTable).

Upvotes: 0

cassandrad
cassandrad

Reputation: 3536

There are no differences, but you can find that the same thing called differently in different programming languages, so how people call something depends on their background and programming language they use. For example: in c++ it will be HashMap and in java it will be HashTable.

Also, there could be one difference concluded based on the naming: HashTable allows only store hashed keys, but not values whereas HashMap allows to retrieve a value by hashed key. Internally the both will use the same algorithm and can be considered as same data structure.

Upvotes: 1

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